Myeloid sarcoma occurring in the maxillary gingiva: a case without leukemic manifestations

Myeloid sarcoma (MS) is a localized extramedullary mass of immature granulocytic cells that usually occurs in patients with acute myeloid leukemia (AML) or myeloproliferative disorders. It may rarely precede peripheral blood or bone marrow involvement, presenting a diagnostic challenge. Although MS may be found in any location, an intraoral occurrence is rare. In this report we describe a rare case of a patient with nonleukemic MS of the maxillary gingiva. The histologic specimen was first interpreted as non-Hodgkin's lymphoma. The correct diagnosis was reached after extensive immunohistologic studies. The malignant cells were myeloperoxidase positive, lysozyme positive, CD45+, CD68+, CD3-, CD10-, CD19-, CD20-, CD30-, CD34-, CD56-, CD79a-, S100-, and chloroacetate esterase negative. Induction therapy with FLAND (fludarabine, Ara-C, mitoxantrone, and dexamethasone) was started, but the patient did not achieve a remission. Some weeks later, the patient presented pleural effusion and paralysis of the seventh cranial nerve on the left side. She died a few days later. The present case indicates the importance of a correct initial diagnosis for adequate therapy, which is often delayed because of a high misdiagnosis rate. If the MS is treated without intensive chemotherapy for AML as soon as possible, the prognosis will be poor.